Arctic Airships, Part 1 - Generating Electricity

Question

This is the first question in my Arctic Airships series of questions. The second one is Arctic Airships, Part 2 - Navigation.

The premise:

An Earth-like planet plunged into an ice age roughly 2,000 years prior to the story. The ice sheets extend to a latitude of about 50 degrees above and below the equator, though I this story (so far) takes place in the planet's Northern Hemisphere. At a latitude of about 67 degrees north are a series of ten or so small villages, each with a population of 500 people.

The technology is roughly that of the late Victorian era - so no automobiles. In fact, there is no clear boundary between icy land and frozen-over water, and it would be extremely dangerous to travel overland in any way. Submarines have not been developed, nor have airplanes; a lack of fossil fuels means that internal combustion engines are nonexistent.

The airships:

The transportation system between villages is an informal fleet of semi-rigid airships. Each is privately owned, and may range in size from 100 feet to 500 feet (30-152 meters) - nothing spectacular. They are a motley bunch, ragged and as patchwork as can be; the one thing that ties them together is that they provide the villages' primary source of power. The one big stride forward has been in photovoltaic cells, and the airships are outfitted with them along much of their body. Wind and hydropower are impractical for various as-yet undetermined reasons; fossil fuels are nonexistent and nuclear power is way too advanced, so this is the only power source for the villages. The engines run on electricity; there are anywhere from four to ten engines on each airship, depending on its size.

The villages are space about 10 miles apart on average - not a lot. The airships provide a sort of taxi service, bringing passengers and freight. The majority of the time, though, they stay aloft, gathering the Sun's energy (ground-based stations are impractical because of the icy terrain, and for some reason airspace near the ground is unstable; cruising altitude is the only place to be).

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Do the airships provide a feasible method of generating power? If so, about how many would be needed to provide the villages with enough electricity, (bearing in mind that the airships consume electricity and stay aloft for long periods of time, as well as that there may not be as much sunlight here as in other parts of the world)?

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Clarifications:

The solar power generation rates and airship engine efficiency rates are comparable to the solar power and airships of today. The engines are comparable to high-class electric motors in both size and efficiency, such as Solar Impulse.

Power is released at each village via charging cables when the airship docks. Electricity is stored onboard in the form of rechargeable batteries which have an essentially infinite lifespan. The energy is needed only for household use - there's no large-scale industry in this world, just small pockets of people. The houses are decently insulated and pretty energy-efficient insofar as they retain heat very well.

Answer 1

http://nunavutenergy.ca/Renewable_Energy

I'd use Nunavut (Canada) as a decent reference point as to solar generation.

"Locations along the Hudson Bay coast in the Kivalliq region receive the highest amount of solar energy in Nunavut. The amount of solar energy that reaches coastal areas of the Kivalliq region is comparable to the amount of solar energy that reaches southern Quebec, much of Ontario, and the Maritimes."

They actually get a decent amount of sun, assuming the Solar cells are put at the correct angle. If you add in these airships are over top of clouds, you should get an added effect of sunlight reflecting from the clouds and amplifying the amount of sunlight actually striking these panels.

As far as energy generation goes, these ships should be able to provide a decent amount of power...more than enough to power a small colony.

That said, there are several challenges:

Most electricity we use is generated 'on demand'...there is very little for storage, energy is needed and we burn fossil fuels to meet the demand.

In this scenario, during night times (and exaggerated during winter months) there are large periods of the day in which there would be no light and therefore no energy. If the colony is far enough north, you would even get periods of 0 sunlight for around 2 weeks.

This means to be truly feasible, you need to either have the population consume energy in time with the sunlight (this includes 0 light during evening hours) or have some advanced version of electrical storage.

Simple solution is they've developed capacitors capable of storing large amounts of energy, or perhaps some battery technology that's capable of transferring to chemical energy for later use.

As more of a social solution...you use the energy when you have it and don't use it when you don't have it. It would give a period in the summer where 24 hour sunlight provides around the clock energy, and a period of 24 hour darkness where there is no electrical use (society tends to hibernate during this time). And of course in-between hours...the difficulty here is most of the population has high points of energy needs, along with low points. Not many of us use electricity in the afternoon....we are off earning a living and other tasks. After dinner, we are consuming electricity at our highest rates...so there would need to be a method of distribution or (once again) some manner of storing the energy during low use periods to use during high use periods.

I'm a little torn on the idea of a gigantic power cable dangling off an airship though. Kinda seems like an anchor pulling you down that you'd have to fight to keep afloat.

added note on daylight:

75 degrees is a long ways north and you're probably not realizing how long the day and night actually are. The transition from 100% daylight to 0% daylight occurs unreasonably fast. cool little tool: http://astro.unl.edu/classaction/animations/coordsmotion/daylighthoursexplorer.html

At 75 degrees, you are looking at roughly Nov 3rd to Feb 7th of complete darkness (3 months, around 100 days). From Feb 7th to May 1, this transitions rapidly from 0 hours to 24 hours of daylight. May 1 to august 10th is 24 hour sunlight (3 months, around 100 days?). And then back to a quick transition to 24 hour darkness by Nov 3rd. Little odd that the transition periods are shorter than the 100% darkness or daylight days.

At 67 degrees, you get about 4 weeks of 24 hour darkness/daylight. I think this is more what you are considering. Apparently at 90 degree's, you get 24 hour daylight or 24 hour darkness with no in between. Sept 22nd - That would be a weird day to see the sun just disappear.

Answer 2

As someone who is working with the winter theme for several years now, I feel partially obligated to chime in.

Really, really cold weather is a complex stuff. It introduces several complications to things that otherwise would be really straigthforward. I could talk about several diferent factors that one should take into account while creating something like this, but for now I will focus on your energy issue, to keep the scope to the question.

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Why do we need power?

Power, be it in the form of heat from a fire or generated by some electric means, is crucial to any kind of more civilized human population. You use it to warm up your kids when it's cold, to work metal, to prepare food, to light up your village when it's dark. We need power to run our machines, to power our vehicles. You need some form of energy to do almost anything more complex on a human settlement, and from where that power comes from really makes a difference.

Conversion = Loss

Anything you do with your avaliable power source will reduce the avaliable amount of power, be it converting it from one form to another, transfering it or just storing it. Even the most advanced batteries we have today can't really store energy forever, losing it slowly over time.

While the sun generates a ton of power [citation needed], you can't exactly tap on it without some big losses.

Let's take this site into account, and do some quick math.

According to this site, the global formula to estimate the electricity generated in output of a photovoltaic system is something like this:

      E = A * r * H * PR

Where:

• E = Energy (kWh)

• A = Total solar panel Area (m²)

• r = solar panel yield (%)

• H = Annual average solar radiation on tilted panels (shadings not included)

• PR = Performance ratio, coefficient for losses (range between 0.5 and 0.9, default value = 0.75)

  So, let's start.

Lets suppose that, somehow, your airship have $9000$ square feet $(30ft\times 300ft)$ of usable solar-colecting area. That's a really big airship, according your parameters. That gives us around $850m^2. $

My source says that Norway receives around $200\text{kWh}$ per square meter... per year. So, let's do a really crude math and split that evenly year-around:

• $200 / 365$ $\approx = 0.55\text{kWh}/m^2$ per day of solar exposure, assuming $100\%$ efficiency.

Most commom modern solar panels of the have something around $15\%$ of efficiency collecting solar power, using advanced manufactoring processes.

That means that a $1m^2$ worth of modern solar panels on a norway-like have a daily output of:

• $0.55 \times 0.15 = 0.0825$ $\text{kWh}$ per square meter per day.

Performance Ratio takes into account disturbances to the solar panels, like dust, snow, a few clouds, power losses generated by the internal structure of the solar panels, and things like that. The default value for modern solar powers is $0.75$. So, taking that into account:

• $0.0825 \times 0.75 \approx= 0.062 \text{kWh}$ per square meter per day. That's around 62 Wh per day per $m^2$.

You could use a light bulb for something like an hour!

So, let's equip our airship with a ton of solar panels.

• $0.062kWh/m^2 \times 850 m^2 = 52.7 \text{kWh}$ worth of power on a daily basis.

  If you devise a super efficient electric heater that uses 1kWh per family (normal heaters use around 1.5kWh to heat a single room) , and keep it on for a full day, one of such ships can only suply the heat demands of two houses.

You would need several airships to power all the houses on your village confortably. Each 850m² airship could power:

• The daily heating needs for 2 houses, or
• 36 modern 60w Ligth Bulbs for a day, or
• 42 10-minutes baths using a 7500w shower, or
• Cook food per 30 minutes 20 times a day using an electric oven.

Most people around the world that really needs heat use some type of oil for heating and coal or gas for cooking. Electric power, while convenient, can become expensive really quick if you don't keep an eye on your usage. I think that, if you want those things to fly around AND power your houses, each family would need at least one 850m² airship.

Also, your airships would be really heavy. Since you don't have wood, you would need some type of ligth material to build then, and a huge amount of power to make them take off. Unless you use some kind of heated gas, like helium, to make them "ligther than air", they can't really fly solar-powered. And, if they do have some gas to make them lighter, they would be really, really propense to accidents, and you can't repair them anymore since you don't have the resources to build them!

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I would like to contribute a bit more to your scenario with some extra considerations:

The Major issues:

• So far north, during an Ice Age, you have an ice sheet. Plant's can't grow on ice sheets, since the soil is far away from the surface.
• Your people don't have wood. You can't grow trees on an ice sheet!
• Your people don't have paper. Since you don't have trees, unless they write directly in leather or stone, they don't really have anything to write on.
• You don't have rubber or easy access to any insulating material, so... that would be a huge problem.
• All of your homes would be glacialy cold. Again, since you don't have wood, you would need to build houses out of stone. I don't have any idea about how they would build such houses.
• Your people can't really mine for any type of mineral. You can't work almost any metal with such tech without fossil fuels or some other type of non-electric power. Since you can't work metal, you can't create the tools needed for true mining.
• Even if at somepoint your people had something avaliable to create tools, tools need constant replacement. They break, become dull, rust, etc. Bone tools only take you so far, you need true metal tools for complex works.
• You don't have any type of cloth avaliable, only leather. Even if you had sheeps, you won't be able to shear them (missing tools) or weave the wool (can't build the machinery to weave it).
• You don't have inks. Since you can't mine and can't really travel, unless you have a ton of exotic, colorful herbs that grow on the extreme cold, your people can't relly color stuff.
• Food is an issue. You basically only have meat for food, and you can't hunt. Your people can't use guns, since they lack the minerals to create them, and they can't use bows, since you don't have wood or other suitable material. You can't use spears, to - no wood! Caribou are really fast animals, and even a baby-caribou can run extremelly fast. Unless your people hunt using stone knives and ambush tatics, your people have some problems. Actually, I don't even know what your caribou would eat, since you can't have any type of plant matter on the surface of an ice sheet.
• You don't have glass. Even if you indeed have sand, you can't create a furnace to melt the sand to create glass. That means, among other things, that you also don't have any kind of lightbulb around anymore.
• It is not possible to have a SolarImpulse-class engine with your avaliable tech. To manufature such engine, you need all the tech around it - which includes high precision, automated manufactoring and advanced eletronics.

My suggestion to you is, if you really want to focus on airship travel, to create a canyon-based world. That way you can use all the normal stuff - trees, fossil fuels, etc, while still barring overland and aquatic transport. People would live on the top of extremely high and extremly steep canions (something like this, just way higher), so they really would need airships to move around if the canions are complex enough. Also, if you create them high enough, they could be way above the clouds, so you can't really see what's down there.

Just my 2¢!

Answer 3

Since we are working within a high latitude ice desert, we have the great example of Antarctica to work with. During the summer, you would be getting around $8\space\text{kilowatts per m}^{2}\space\text{per day,}$ which is impressive.

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About $0.3\text{ kilowatts per m}^2 \space\text{per hr}$, on account of the three months of constant light at $75$ degrees. During the winter though, you would have nearly no available energy: maybe $0.5\text{ kilowatt hours per m}^2\text{ a day}.$

Since you specified the size ($100-500$ ft long), I'll take a historical sample in the within that range: the Zeppelin LZ 120 Bodensee, at $396$ ft long. It had 4 245 horsepower engines; this is about 183 Kilowatts. Combined, $732$ kilowatts.

Assuming perfect efficiency (which you wouldn't have, the best we have today is $44\%$ efficient), you would need about $2200\space m^2$ to power the ship ($732\text{ kW/0.33 kW per m}^2$.). This is larger than the area of the top of the airship, meaning that it wouldn't be able to power itself constantly. But the airship wouldn't always be moving, so it could charge during the most of the day it's not ferrying people. I imagine villages so small wouldn't need many ferries. A society like that of the early 1900s wouldn't require too much energy, so the airship could provide a few hundred kilowatts to the village (so like a kilowatt a person a day). Whatever the case may be, your people wouldn't have a whole lot to work with.

In the end, winter seems to be a nearly impossible obstacle to overcome. No sun would grind everything to a halt.

Answer 4

This post is unrelated to feasibility, but I'd like to give a suggestion as to how to make this world a bit more feasible.

Most of the comments discussing feasibility follow tow lines: why are these people living in such an utterly inhospitable environment, and how are they manufacturing airship components and advanced fuel cells up there.

Over the course of 2000 years, I'd expect people to expand beyond a few small villages, given sufficient resources, and to adapt to the environment better than just about anyone on earth right now. It seems like, in order for people to live in a small population that far north, they need a very compelling reason to stay. In a world depleted of fossil fuels, however, there is one good reason to venture to Northern Alaska in an ice age: oil.

What if these people have been sent here from regions further to the south that need oil products for producing their advanced technology? The airship nomads could harvest oil without even needing to drill for it if they're experts at scavenging old technology buried under the ice. Without having any knowledge of the drilling processes, they could mine down through the glaciers to the old prospecting towns and drain oil, lubricants, and anything else valuable from the old oil drilling equipment, as well as salvaging machinery.

All of this could get flown south on their airships, which may not be as good as skis/kayaks for short, overland journeys, but would definitely be superior for transporting large quantities of goods given that the Northern ocean is completely iced in. In exchange for their oil products, which they themselves don't use, but which are more valuable than gold to the southern industrialists, the airship nomads receive solar panels, capacitors, and other technological goodies from their southern neighbors. They themselves don't have the technology to produce such things, being of a Victorian level of technological development without the infrastructure in place to really go much beyond that, but they can trade for some of them.

Answer 5

Living so far north for such long time would be easier if your heroes adapted to rugged life of Eskimo (if over sea, fishing and hunting) or Sami (if overland, following caribou herds).

Eskimo way is more flexible (easier to get out to south - but for unknown reason they never did: when polar explorers met them, they thought Eskimo are the only people on Earth), so if you want your heroes to be stuck, put them beyond high mountain range and make sea narrows around it too turbulent to freeze. Unlikely will any plant grow there, it is all hunting, fishing and gathering.

Good energy source would be seal and whale blubber. You need to be aware of rabbit starvation - if diet consists from lean meat only - you need fat, and adequate level of fat is important for brain development. Your people will starve on lean caribou meat diet. Fishing salmon is other good idea (if you do not want to go to ice to hunt seals).

Small isolated groups of people are at risk to lose technology, even if very primitive, read article about Tasmanian tribesmen link thanks to @Serban Tanasa - about how 5000 Tasmanians lost elementary skills like fishing and bone tools.

If you really want to fly out over the mountains, better bet would be hot air balloons heated by blubber. Not sure what would be good light material to make balloons. Maybe you can establish some fish with big swim bladder, fill it with methane, and use it to be lighter when going over mountains.

BTW those high mountains to the south your heroes need to cross also make huge shade, making your solar energy even less plausible. Just sayin'.

I promised a link about part of Canada NOT covered by glaciers during last glaciation period: Cypress Hills - the northernmost point in North America that remained south of the continental ice sheets during the Wisconsin glaciation.

There is no reason why group of determined and well provisioned explorers, during decade with improved weather, could not find a pass over mountains. People cross Himalayas. Even crossing glaciers. In worst case they can go multi-camp campaign, most people hauling provisions for next year attempt. There should be some legends about better life farther south - you can use that drive to power your story, instead of solar airships.

More interesting facts about Arctic methane

You may have hard time to maintain metal-oriented technology with so little fuel available for smelting. Your people may revert to copper-age technologies if they can find a vein of 99% pure copper like Old Copper Complex - your people don't have to melt it, so no fuel is needed, just hammer it to shape they need.

Funny how Amerindians abandoned best copper mine of all Bronze Age 3K years ago.